unionKeys

Gives keys present in any map. 🏃 📼 📦 🌔 📒

Similar: unionKeys, intersectionKeys.

map.unionKeys(...xs);
// xs: maps

const map = require("extra-map");

var x = new Map([["a", 1], ["b", 2], ["c", 3], ["d", 4]]);
var y = new Map([["b", 20], ["c", 30], ["e", 50]]);
map.unionKeys(x, y);
// Set(5) { "a", "b", "c", "d", "e" }

references

• Data.Set.union: Haskell
• Set.union: Python
• _.union: lodash
• _.unionBy: lodash
• _.unionWith: lodash
• Array.union: sugarjs